<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 200px;
            height: 200px;
            padding: 50px;
            border: 50px solid rgba(0,0,0,0.3);

            background-image: url(./assets/bk.jpg);
            background-repeat: no-repeat;

            /* 
            背景图的定位区域：
            border-box 边框
            padding-box 内边距
            content-box 内容区

            */
            background-origin: border-box;
            background-origin: padding-box;
            background-origin: content-box;
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>